There was certainly no shortage of unique computers on display at the 2021 Vintage Computer Festival East; that’s sort of the point. But even with the InfoAge Science and History Museum packed to the rafters with weird and wonderful computing devices stretching back to the very beginning of the digital age, Alastair Hewitt’s Novasaur was still something of an oddity.
In fact, unless you knew what it was ahead of time, you might not even recognize it as a computer. Certainly not a contemporary one, anyway. There’s nothing inside its Polycase ZN-40 enclosure that looks like a modern CPU, a bank of RAM, or a storage device. Those experienced with vintage machines would likely recognize the tight rows of Advanced Schottky TTL chips as the makings of some sort of computer that predates the 8-bit microprocessor, but its single 200 mm x 125 mm (8 in x 5 in) board seems far too small when compared to the 1970s machines that would have utilized such technology. So what is it?
Inspired by projects such as the Gigatron, Alastair describes the Novasaur as a “full-featured personal computer” built using pre-1980 components. In his design, 22 individual ICs stand in for the computer’s CPU, and another 12 are responsible for a graphics subsystem that can push text and bitmapped images out over VGA at up to 416 x 240. It has 512 K RAM, 256 K ROM, and is able to emulate the Intel 8080 fast enough to run CP/M and even play some early 80s PC games.
Better Living Through Emulation
Arguably the most noteworthy feature of the Novasaur is it’s ability to emulate a vintage CPU. By taking this approach, Alastair essentially ensured that the only software he’d ever technically have to write for the computer would be a hardware abstraction layer. Once that was in place, he could simply load up existing programs and operating systems that were designed to run on the emulated chip.
In comparison, other TTL computers generally need to have new applications written for them. To use the Gigatron as an example, the system’s ROM provides the user with a handful of tools and games that were written specifically for the hardware. But outside of that, your best bet for getting new software on the system would be to use the Tiny BASIC interpreter and write it yourself.
Intel 8080 Credit: Konstantin Lanzet [CC BY-SA 3.0]
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The Novasaur’s ability to run CP/M and existing Intel 8080 software makes it a far more practical machine than others we’ve seen in the past, and is central to the claim of it being a “full-featured personal computer” rather than just an experiment in computing minimalism. But interestingly, a look through the project log shows that the decision to go with the 8080 didn’t happen …read more
Source:: Hackaday